I'd say the same abouit a few Tarantino films. I absolutely loved (and still do) Reservoir Dogs and Pulp Fiction but he hasn't done anything to touch them since.

Inglorious Basterds had a totally compelling opening scene but by the end it had become gratuitous and boring. Same with Django Unchained - I completely lost interest with the predictable politically correct ending. I expected something more original than Hollywood morality.